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