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