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