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