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