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