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