svg and directed graphs

Hello,

I am looking for a possibility to express some xml data in a directed 
graph. As file format for graphs I discoverd GraphML 
(http://graphml.graphdrawing.org/). Do you know of any stylesheets that 
transform the GraphML data into a svg graph?
If there is another format for storing graphs which can easily be 
transformed to svg please let me know.

Regards,
Garvin