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