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