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