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