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