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