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