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