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