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