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