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