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