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