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