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