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