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