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