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