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