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