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