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