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