Graphs created and saved in the Graph Modeling Language (.gml) can be exported to SVG vector graphics with programs like the yEd which should support both of these file types. Likely only the shape of the graph is exported.
However, the GML extension is also used for maps Geography Markup Language which can probably also be converted to XML graphics (.svg files) with proper GIS/GPS navigation conversion software, which is another type of possible gml to svg conversion.