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