A good read or two would be the Honor Harrington series. Its not exactly Traveller (and the ships have much greater accelerations), but the tactics would be pretty much similar.
Dreadnaughts, SD's and BB's organize themselves into the "wall of battle" so as to maximize their collective broadsides and concentration of fire. The cruisers, destroyers, and other ships in the "screen" then spread out to assist in providing the counter missile fire.
In Traveller, where ships don't have a broadside (per se), this probably wouldn't change too much, as the wall formation gives you the greatest offensive overlap of fire from all ships involved.
Borrowing from the maneuvers used by tanks in land warfare, one could also extrapolate the following formations:
WALL: already described
CONE: used for probing forces. The ships in this formation are arranged into a three dimensional wedge or hollow cone. The lead ship is responsible for forward coverage in a 90° cone. Each ship out the side is responsible to cover sectors of fire ranging from 10° out from the ship ahead to 10° ahead of the ship to the stern. This formation limits offensive fire in exchange for better sensor coverage when probing an enemy controled area.
This formation is also good for penetrating an enemy wall, as the exposed areas are masked by the leading ships until the wall is penetrated, when the flanking sides of the cone then have the concentration advantage over the now perpendicular wall.
ESCHELON LEFT/RIGHT/UP/DOWN: A variant of the wall formation, which is sloped 30° to one side. This is used in place of the cone when contact is anticipated from one flank.
SPHERE: A defensive formation used to protect or evacuate non-combattants or wounded ships from the battlefield. This formation sacrifices concentration of firepower in exchange for wide area coverage. It is also an effective anti-fighter formation.
COLUMN: Not a recomended combat formation. Ships are arranged into a set of parallel lines for ease of travel.
STAGGERED COLUMN: A travelling formation with some defensive precautions. This formation flanks a standard column with fighting ships in a helical pattern. This is good for piracy suppression, but vastly inferior if contact is ancticipated.
In the case of your carier group, your principle threat (at least most of the time) is enemy fighters and light elements. A sphere formation would probably be best, with the carier in the center, cruisers to fore and aft, and destroyers in a tripod around the axis of travel.
In HG terms, this formation has all of your elements in the reserve or on the line (depending on how you look at it, and where they are in the fight)
When under contact from heavier elements, the cruisers and destroyers would re-deploy into a wall or eschelon in effort to protect the carier while the fighters did their best to bring the intruder under fire.
In HG terms, this places your carier into the reserve for most of the fight, with the screening elements on the line.
Your mileage may vary.