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