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