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