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