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