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