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