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