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