One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(3,7)(9,10)(11,16)(12,22)(13,27)(14,29)(15,19)(17,25)(18,23)(20,33)(21,32)(24,35)(26,39)(28,40)(30,34)(31,38)(36,37) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11,15,14)(10,16,19,29)(12,20,24,26)(13,21,28,23)(17,30,31,36)(18,27,32,40)(22,33,35,39)(25,34,38,37)(9,12,23,37,14,26,28,38,15,24,21,34,11,20,13,25)(10,17,27,33,16,30,32,35,19,31,40,39,29,36,18,22)(2,5)(6,8)(9,11,15,14)(10,16,19,29)(12,20,24,26)(13,21,28,23)(17,30,31,36)(18,27,32,40)(22,33,35,39)(25,34,38,37)(1,3,4,7)(2,6,5,8)(12,24)(17,31)(20,26)(22,35)(25,38)(30,36)(33,39)(34,37)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.