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