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