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