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