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