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