...
    graph = new GraphViewer(new NonMovableGraph(parent, SWT.NONE));
    graph.setLabelProvider(new MyLabelProvider());
...
private class MyLabelProvider extends LabelProvider implements IFigureProvider {
    @Override
    public IFigure getFigure(final Object element) {
      if (element instanceof MyNode) {
        MyNode c = (MyNode) element;
        return new MyNodeFigure(c);
      }
      return null;
    }

    @Override
    public String getText(final Object element) {
      if (element instanceof EntityConnectionData) {
        return null;
      }
      return super.getText(element);
    }
  }