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