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