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)(11,21)(12,13)(14,19)(15,33)(16,24)(17,29)(18,32)(20,27)(22,39)(23,26)(25,36)(28,31)(30,40)(34,38)(35,37) involution — undirected(2,5)(6,8)(9,11,14,24)(10,16,19,21)(12,26,28,40)(13,30,31,23)(15,34,27,25)(17,37,32,39)(18,35,29,22)(20,38,33,36)(1,3,4,7)(2,6,5,8)(9,12,27,18,14,28,15,29)(10,17,33,31,19,32,20,13)(11,22,34,40,24,35,25,26)(16,30,38,39,21,23,36,37)(9,13,15,32,14,31,27,17)(10,18,20,12,19,29,33,28)(11,23,25,39,24,30,34,37)(16,35,36,40,21,22,38,26)(2,5)(6,8)(10,19)(12,28)(16,21)(18,29)(20,33)(22,35)(26,40)(36,38) 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.