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)(13,14,17,19)(15,16,20,18)(22,25)(23,27)(5,7)(6,10)(8,11)(9,12)(13,15,17,20)(14,18,19,16)(21,22)(23,26)(24,25)(27,28)(7,12)(10,11)(14,19)(15,20)(21,23,24,27)(22,26,25,28)(1,2,3,4)(5,8,9,6)(7,10,12,11)(13,16,17,18)(14,20,19,15)(21,22)(23,26)(24,25)(27,28)(5,7)(6,11)(8,10)(9,12)(13,14)(15,18)(16,20)(17,19)(21,23)(22,26)(24,27)(25,28) involution — undirectedA 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.