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