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