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