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