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