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)(11,14)(12,16)(13,17)(15,18)(19,22)(20,23)(21,24)(25,26,31,34,30,35,29,38)(27,33,36,39,28,32,37,40)(2,5)(3,7)(9,11,13,18)(10,14,17,15)(12,20,21,19)(16,23,24,22)(25,27)(26,32)(28,30)(29,37)(31,36)(33,35)(34,40)(38,39)(9,11)(10,15)(12,19)(13,18)(14,17)(16,23)(20,21)(22,24)(25,26)(27,33)(28,32)(29,34)(30,35)(31,38)(36,40)(37,39) involution — undirected(1,3,4,7)(2,6,5,8)(11,18)(14,15)(19,20)(22,23)(25,28,30,27)(26,33,35,32)(29,36,31,37)(34,39,38,40)(2,5)(6,8)(9,12,13,21)(10,16,17,24)(11,19,18,20)(14,22,15,23)(25,29,30,31)(26,34,35,38)(27,36,28,37)(32,39,33,40)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.