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