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