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)(26,32)(27,35)(28,38)(30,40) involution — undirected(1,2,5,6)(3,4,7,8)(11,17)(15,21)(18,23)(22,24)(25,26,31,32)(27,33,35,29)(28,34,38,37)(30,39,40,36)(2,6)(3,7)(10,14)(15,21)(16,19)(22,24)(25,27)(26,33)(28,39)(29,32)(30,37)(31,35)(34,40)(36,38) involution — undirected(9,10)(11,15)(12,16)(13,14)(17,21)(18,22)(19,20)(23,24)(25,28)(26,34)(27,36)(29,40)(30,33)(31,38)(32,37)(35,39) involution — undirected(1,3)(2,4)(5,7)(6,8)(9,11)(10,15)(12,18)(13,17)(14,21)(16,22)(19,24)(20,23)(25,29,31,33)(26,35,32,27)(28,40,38,30)(34,39,37,36)(1,4)(2,3)(5,8)(6,7)(9,12)(10,16)(11,18)(13,20)(14,19)(15,22)(17,23)(21,24)(25,30,31,40)(26,36,32,39)(27,37,35,34)(28,33,38,29)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.