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