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