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