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