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