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