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