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