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