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