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