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