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