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