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