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