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