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