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