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