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