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