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