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