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