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