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