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