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