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