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