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