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