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