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