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