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