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