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)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26,29,34)(27,36,38,31)(28,35,30,33)(32,39,40,37)(3,7)(5,8)(9,11,13,19)(10,14,16,17)(12,18,20,24)(15,21,22,23)(25,27,29,38)(26,31,34,36)(28,39,30,37)(32,33,40,35)(1,3)(2,5)(4,7)(6,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,27,29,38)(26,32,34,40)(28,37,30,39)(31,33,36,35)(3,7)(5,8)(10,16)(12,20)(14,17)(18,24)(25,27)(26,31)(28,39)(29,38)(30,37)(32,35)(33,40)(34,36) involution — undirected(2,6)(5,8)(10,16)(14,17)(15,22)(21,23)(25,28,29,30)(26,33,34,35)(27,37,38,39)(31,32,36,40)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.