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