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