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