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