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