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