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