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