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