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