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