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