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