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