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