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