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