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