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