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