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