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