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