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