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