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