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