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