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