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