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