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