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