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