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