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