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