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