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