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