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