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