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