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