Graph drawing of matrices in the University of Florida Sparse Matrix Collection. These tend to have a lot more structure than the large sparse graphs one gets from e.g. internet connectivity, and many of the drawings show that — for instance, for sparse matrices derived from finite element meshes, the drawing often shows the approximate shape of the meshed object, despite being drawn using only the graph connectivity as input. There are a lot of drawings, too: 95 pages of thumbnails. Via infosthetics.

A graph from the Florida Sparse Matrix Collection