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