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