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