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