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