One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,7)(3,6,4,8)(9,10,12,13)(11,14,16,15)(17,18,21,25)(19,26,27,31)(20,23,30,24)(22,29,32,28)(1,3,5,4)(2,6,7,8)(9,11)(10,14)(12,16)(13,15)(17,19,21,27)(18,22,25,32)(20,29,30,28)(23,26,24,31)(1,4,5,3)(2,6,7,8)(10,13)(11,15)(14,16)(18,23)(19,27)(20,30)(22,31)(24,25)(26,32) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.