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