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