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