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