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