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