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