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