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