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