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