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