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