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