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