Agregar dependencia a tu Index.html

    <!-- AngularJS -->
     <script src="bower_components/gojs/release/go.js"></script>

Agregar como directiva

    .directive('goDiagram', function() {
    return {
        restrict: 'E',
        template: '<div></div>',  // just an empty DIV element
        replace: true,
        scope: { model: '=goModel' },
        link: function(scope, element, attrs) {

            if (window.goSamples) goSamples(); // init for these samples -- you don't need to call this

            var $ = go.GraphObject.make;
            var diagram =  // create a Diagram for the given HTML DIV element
                $(go.Diagram, element[0],
                    {
  
                        nodeTemplate: $(go.Node, "Auto", 
                            new go.Binding("location", "loc", go.Point.parse).makeTwoWay(go.Point.stringify),
                            $(go.Shape, "RoundedRectangle", new go.Binding("fill", "color"),
                                {
                                    portId: "", cursor: "pointer", strokeWidth: 0,
                                    fromLinkable: false, toLinkable: false,
                                    fromLinkableSelfNode: false, toLinkableSelfNode: false,
                                    fromLinkableDuplicates: false, toLinkableDuplicates: false
                                }),
                            $(go.TextBlock, { margin: 8, editable: false, alignment: go.Spot.Center },
                                new go.Binding("text", "name").makeTwoWay())
                        ),
                        linkTemplate: $(go.Link,
                            { relinkableFrom: true, relinkableTo: true },
                            $(go.Shape),
                            $(go.Shape, { toArrow: "Standard", stroke: null, strokeWidth: 0 })
                        ),
                        initialContentAlignment: go.Spot.Center,
                        initialDocumentSpot : go.Spot.Center, 
                        initialViewportSpot: go.Spot.Center,
                        "ModelChanged": updateAngular,
                        "ChangedSelection": updateSelection,
                        "undoManager.isEnabled": false
                    });
                      
    //              diagram.initialContentAlignment = go.Spot.Center;
                   diagram.requestUpdate(); // Needed!
            function updateAngular(e) {
                if (e.isTransactionFinished) {
                    scope.$apply();
                }
            }

            // update the Angular model when the Diagram.selection changes
            function updateSelection(e) {
                diagram.model.selectedNodeData = null;
                var it = diagram.selection.iterator;
                while (it.next()) {
                    var selnode = it.value;
                    // ignore a selected link or a deleted node
                    if (selnode instanceof go.Node && selnode.data !== null) {
                        diagram.model.selectedNodeData = selnode.data;
                        break;
                    }
                }
                scope.$apply();
            }

            // notice when the value of "model" changes: update the Diagram.model
            scope.$watch("model", function(newmodel) {
                var oldmodel = diagram.model;
                if (oldmodel !== newmodel) {
                    diagram.removeDiagramListener("ChangedSelection", updateSelection);
                    diagram.model = newmodel;
                    diagram.addDiagramListener("ChangedSelection", updateSelection);
                }
            });

            scope.$watch("model.selectedNodeData.name", function(newname) {
                if (!diagram.model.selectedNodeData) return;
                // disable recursive updates
                diagram.removeModelChangedListener(updateAngular);
                // change the name
                diagram.startTransaction("change name");
                // the data property has already been modified, so setDataProperty would have no effect
                var node = diagram.findNodeForData(diagram.model.selectedNodeData);
                if (node !== null) node.updateTargetBindings("name");
                diagram.commitTransaction("change name");
                // re-enable normal updates
                diagram.addModelChangedListener(updateAngular);
                diagram.initialContentAlignment = go.Spot.Center;

            });
        }
    };
})

Minimal Sample

Graphs are constructed by creating one or more templates, with desired properties data-bound, and adding model data.

<script src="go.js"></script>

<script id="code">
  function init() {
    var $ = go.GraphObject.make;  // for conciseness in defining templates

    var myDiagram = $(go.Diagram, "myDiagramDiv",  // create a Diagram for the DIV HTML element
                  {
                    // enable undo & redo
                    "undoManager.isEnabled": true
                  });

    // define a simple Node template
    myDiagram.nodeTemplate =
      $(go.Node, "Auto",  // the Shape will go around the TextBlock
        $(go.Shape, "RoundedRectangle", { strokeWidth: 0, fill: "white" },
          // Shape.fill is bound to Node.data.color
          new go.Binding("fill", "color")),
        $(go.TextBlock,
          { margin: 8 },  // some room around the text
          // TextBlock.text is bound to Node.data.key
          new go.Binding("text", "key"))
      );

    // but use the default Link template, by not setting Diagram.linkTemplate

    // create the model data that will be represented by Nodes and Links
    myDiagram.model = new go.GraphLinksModel(
    [
      { key: "Alpha", color: "lightblue" },
      { key: "Beta", color: "orange" },
      { key: "Gamma", color: "lightgreen" },
      { key: "Delta", color: "pink" }
    ],
    [
      { from: "Alpha", to: "Beta" },
      { from: "Alpha", to: "Gamma" },
      { from: "Beta", to: "Beta" },
      { from: "Gamma", to: "Delta" },
      { from: "Delta", to: "Alpha" }
    ]);
  }
</script>