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