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