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