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