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