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