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