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