tulip might be what you want; I'm not sure if the viz. is built-in or just something others have done with it though. But well worth knowing about, for all inte

tulip might be what you want; I'm not sure if the viz. is built-in or just something others have done with it though. But well worth knowing about, for all interesting in graph viz. http://tulip.labri.fr/TulipDrupal/