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