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