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