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