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