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