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