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