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