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