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