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