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