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