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