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