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