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