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