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