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