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