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