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