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