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