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