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