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