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)(11,22)(12,27)(13,19)(14,30)(15,31)(16,35)(17,24)(18,26)(20,28)(21,23)(25,39)(29,36)(32,37)(33,38)(34,40) involution — undirected(2,5)(6,7)(9,11)(10,17)(12,28)(13,24)(14,29)(15,32)(16,33)(18,35)(19,22)(20,39)(21,38)(23,26)(25,34)(27,40)(30,37)(31,36) involution — undirected(9,12,28,24,16,29,15,33,13,25,34,11,23,32,14,26)(10,18,30,37,21,22,40,39,19,38,31,36,35,17,20,27)(1,3,4,8)(2,6,5,7)(10,19)(17,22)(18,38)(20,40)(21,35)(27,39)(30,31)(36,37)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.