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