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