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