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