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