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