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