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