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