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