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