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