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