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