Fullerene symmetries

Continuing the theme of colored graphs, some of the more interesting examples are fused ring structures, especially those with some symmetries, but not completely symmetrical. Fullerenes fit this description, for example this 26 atom example:

the distribution of colors might look a little odd, but the dark blue atom surrounded by three cyan atoms is actually repeated at the top - which is really the other side of the sphere. These kind of 3D molecules don't lay out very well with the CDK's layout code, so I used JChempaint instead to make a more symmetric 28-fullerene:

This is actually a screengrab of a crude viewer I put together (commit) that takes a molfile and calculates the signatures. Selecting a signature from the right hand list highlights it on the graph. Anyway, it's easier than making images like this by hand:

Except that the little graph at the bottom (which is a quotient graph) can't be drawn by the renderer as it has loop-edges.