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