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