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