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