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