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