Presenting... "The Eye of Blender"!
As with all large graphs, I've ended up having to use neato (instead of dot) to get it to render without crashing after several hours of full-on crunching. One of the most interesting features though is how many sequential chains of operations there are everywhere - clearly many opportunities for parallelism abound, though many of the bugs in the system currently mean that we don't actually get very much performance just yet.
It's always surprising when glitchy software ends up creating bizzare yet surreal images. In this case, what looks like an eye (and in Blender colours too).