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