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