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