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