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