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