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