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