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