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