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