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