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