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)(27,32,37,33,28,38,39,40)(1,3,4,8)(2,5,6,7)(9,11,14,19)(10,16,12,18)(13,20,15,22)(17,23,21,24)(25,27,30,37,31,28,29,39)(26,32,35,33,36,38,34,40)(9,12,14,10)(11,18,19,16)(13,17,15,21)(20,23,22,24)(25,28)(26,33)(27,31)(29,39)(30,37)(32,35)(34,38)(36,40)(2,6)(5,7)(11,19)(16,18)(20,22)(23,24)(25,29,31,30)(26,34,36,35)(27,37,28,39)(32,33,38,40)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.