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