One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,8)(4,6)(5,7)(17,18)(19,28)(20,26)(21,27)(22,24)(23,31)(25,30)(29,32) involution — undirected(1,3,5,4)(2,6,7,8)(9,10)(11,15)(12,14)(13,16)(18,24)(19,29)(26,30)(27,31)(9,11)(10,13)(12,16)(14,15)(17,19,23,30,22,29,21,26)(18,25,27,28,24,20,31,32)(11,16)(13,15)(17,20)(18,26)(19,27)(21,28)(22,25)(23,32)(24,30)(29,31) involution — undirected(1,4,5,3)(2,6,7,8)(10,14)(13,15)(17,21,22,23)(18,27,24,31)(19,26,29,30)(20,32,25,28)A 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.