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