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)(25,26,29,32)(27,34,35,31)(28,37,39,33)(30,38,40,36)(1,3,4,7)(2,5,6,8)(9,11)(10,14)(12,18)(13,17)(15,22)(16,21)(19,24)(20,23)(25,27,29,35)(26,30,32,40)(28,38,39,36)(31,37,34,33)(2,6)(5,8)(11,17)(14,21)(18,23)(22,24)(25,27)(26,31)(28,36)(29,35)(30,33)(32,34)(37,40)(38,39) involution — undirected(11,17)(14,21)(18,23)(22,24)(27,35)(30,40)(31,34)(36,38) involution — undirected(9,12,13,20)(10,15,16,19)(11,18,17,23)(14,22,21,24)(26,32)(30,40)(31,34)(33,37)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.