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