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