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