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