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