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)(11,15)(12,13)(14,16)(17,18)(19,24)(20,23)(21,22)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,40)(37,38)(2,6)(3,7)(9,11,14,19)(10,15,16,24)(12,22,18,20)(13,21,17,23)(26,31)(28,37)(32,40)(34,35)(1,3)(2,4)(5,7)(6,8)(10,16)(11,19)(12,18)(21,23)(25,27)(26,32)(28,35)(29,38)(30,36)(31,40)(33,39)(34,37) involution — undirected(1,4)(2,3)(5,8)(6,7)(9,12,14,18)(10,17,16,13)(11,20,19,22)(15,21,24,23)(25,28,30,37)(26,33,31,38)(27,35,36,34)(29,32,39,40)(9,11)(10,15)(12,20)(13,23)(14,19)(16,24)(17,21)(18,22)(25,29)(26,34)(27,33)(28,32)(30,39)(31,35)(36,38)(37,40) involution — undirected(9,13,14,17)(10,18,16,12)(11,21,19,23)(15,20,24,22)(25,27)(26,32)(28,35)(29,38)(30,36)(31,40)(33,39)(34,37)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.