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