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