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