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