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)(11,14)(12,19)(13,15)(16,20)(17,23)(18,21)(22,24)(29,37)(34,38)(35,40)(36,39)(2,5)(6,7)(9,11,13,18)(10,14,15,21)(12,17,20,24)(16,22,19,23)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,40)(37,38)(1,3)(2,6)(4,8)(5,7)(10,15)(14,21)(16,19)(22,23)(26,31)(28,32)(34,38)(36,39) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11)(10,14)(12,17)(13,18)(15,21)(16,22)(19,23)(20,24)(25,27,30,33)(26,32,31,28)(29,35,37,40)(34,39,38,36)(9,10)(11,14)(12,16)(13,15)(17,22)(18,21)(19,20)(23,24)(25,28,30,32)(26,33,31,27)(29,36,37,39)(34,40,38,35)(9,12,13,20)(10,16,15,19)(11,17,18,24)(14,22,21,23)(25,29)(26,34)(27,35)(28,36)(30,37)(31,38)(32,39)(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.