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