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