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