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