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