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