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