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