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