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