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)(11,15,16,13)(19,23)(20,22)(25,26,30,31)(27,28,35,32)(29,37,38,33)(34,39,40,36)(1,2,4,6)(3,5,8,7)(11,16)(13,15)(17,18,21,24)(19,20,23,22)(26,31)(28,32)(29,38)(34,40)(1,2)(3,5)(4,6)(7,8)(9,10)(11,13)(12,14)(15,16)(17,19,21,23)(18,22,24,20)(25,27,30,35)(26,32,31,28)(29,34,38,40)(33,39,37,36)(1,2)(3,5)(4,6)(7,8)(9,11)(10,13)(12,16)(14,15)(17,18)(19,22)(20,23)(21,24)(25,28,30,32)(26,27,31,35)(29,36,38,39)(33,34,37,40)(1,3,4,8)(2,5,6,7)(9,10)(11,13)(12,14)(15,16)(17,20,21,22)(18,23,24,19)(25,29)(26,33)(27,34)(28,36)(30,38)(31,37)(32,39)(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.