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