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