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