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