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