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