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