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