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