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