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