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