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