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