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