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