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