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