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)(15,24)(16,20)(17,22)(18,27)(19,23)(21,25)(26,28) involution — undirected(1,2)(3,4)(5,7,8,12)(6,9,10,11)(13,14)(15,24)(16,20)(17,22)(18,27)(19,23)(21,25)(26,28)(13,15,19,25)(14,20,23,28)(16,18,26,17)(21,27,24,22)(2,4)(13,16,19,26)(14,21,23,24)(15,17,25,18)(20,22,28,27)(6,10)(9,11)(13,17,19,18)(14,22,23,27)(15,16,25,26)(20,21,28,24)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.