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