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