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