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