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