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