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)(15,16,19,20)(22,25)(23,27)(1,2,4,3)(5,6,8,10)(7,9,12,11)(14,18)(15,19)(1,3,4,2)(13,15)(14,16)(17,19)(18,20)(21,22)(23,26)(24,25)(27,28)(5,6)(7,9)(8,10)(11,12)(13,15)(14,16)(17,19)(18,20)(21,23,24,27)(22,26,25,28)(5,7)(6,9)(8,12)(10,11)(13,16)(14,15)(17,20)(18,19) 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.