Hi,
John Moran and myself wrote a javascript graph library that allows a user to specify in a JSON file or object a graph (node and edges) along with other Babylon.js mesh properties for the edges and nodes. Our builder then renders the graph in a Babylon scene.
The source code is on GitHub (http://github.com/erimcg/yagl) and a demo can be found at http://demo.yagljs.com/basic/basicScene.html.
Let us know what you think! ~Eric