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