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