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