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)(25,26,31,28)(27,32,37,38)(29,33,30,34)(35,39,40,36)(1,3,4,7)(2,5,6,8)(9,11,14,20)(10,15,17,18)(12,19,13,22)(16,23,21,24)(25,27)(26,32)(28,38)(29,36)(30,39)(31,37)(33,35)(34,40)(2,6)(5,8)(25,28,31,26)(27,35,37,40)(29,33,30,34)(32,39,38,36)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(25,29,31,30)(26,33,28,34)(27,36,37,39)(32,35,38,40)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(27,36)(29,30)(32,35)(33,34)(37,39)(38,40)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.