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