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