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