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