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