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