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