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