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