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)(11,12)(13,15)(14,16)(17,18,21,22)(19,20,23,24)(26,30)(27,33)(28,36)(39,40)(9,11)(10,14)(12,15)(13,16)(17,18)(19,20)(21,22)(23,24)(25,26,29,30)(27,31,33,34)(28,37,36,32)(35,40,38,39)(9,11,13,16)(10,12,15,14)(17,19,21,23)(18,20,22,24)(25,26)(27,34)(28,37)(29,30)(31,33)(32,36)(35,39)(38,40)(1,2)(3,5)(4,6)(7,8)(9,12,13,14)(10,11,15,16)(17,20,21,24)(18,19,22,23)(25,27)(26,31)(28,38)(29,33)(30,34)(32,40)(35,36)(37,39)(1,3,4,7)(2,5,6,8)(9,11)(10,12)(13,16)(14,15)(17,19)(18,20)(21,23)(22,24)(25,28)(26,32)(27,35)(29,36)(30,37)(31,39)(33,38)(34,40)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.