In response to the request for "a visualization of the hexahedral graph 5":
HexahedraPolyhedron http://cs.smith.edu/~orourke/MathOverflow/HexahedralGraph.jpg
Just to illustrate the point that there are multiple realizations of any polyhedral graph:
Wheel5Graph http://cs.smith.edu/~orourke/MathOverflow/Wheel5ab.jpg