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