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