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