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