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