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