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