One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,11)(8,12)(9,10)(14,18)(19,27)(20,28)(21,25) involution — undirected(2,3)(6,10)(11,12)(13,14,16,18)(15,19,22,27)(17,25,24,21)(20,26,28,23)(1,2,4,3)(5,7,9,8)(6,11,10,12)(13,15)(14,19)(16,22)(17,23)(18,27)(20,25)(21,28)(24,26)(1,3,4,2)(5,8,9,7)(6,12,10,11)(13,15)(14,20)(16,22)(17,26)(18,28)(19,25)(21,27)(23,24)(6,10)(11,12)(15,22)(19,27)(20,28)(23,26) involution — undirectedA 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.