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