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