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