Predators’ suits give them the ability to become invisible, this is fine if  the Predator doesn’t move, Future War has a simple mechanism for dealing with hidden troops lying in wait to ambush. However, a Predator prefers to move and hunt so this won’t do. Moving an invisible model by map or written commands etc is a very tedious thing to do and completely against the spirit of a Future War game so instead I suggest the following:
You can use a marker next to the figure to denote an invisible Predator or perhaps a blip counter such as those available from Litko, a clear resin Predator from Ainsty Castings , or a standard figure painted to resemble an invisible one, white or jungle patterned might look ok.
I've used the resin Ainsty figures for my Predators.

An invisible Predator rolls 3 dice every time an enemy wants to shoot at it. Each dice that is 3+ removes a shooting dice form each attacker; this is in addition to any cover bonus.
E.g. An invisible Predator moves into a forest area in sight of 2 human stands, a rifle squad (3 dice) and a HMG (4 dice). Both decide to form a fire group and try some reaction fire.
The Predator rolls 3 dice, scoring 1,2,5.
The 5 removes a firing die from each attacking stand leaving the rifle squad with 1 die (3 dice, -1 for forest cover, -1 for Predator score of 5) and the HMG with 2 dice (4 dice, -1 for forest cover, -1 for Predator score of 5).
The human player decides to open fire with the HMG rolling 5,6 which suppresses the Predator and makes it visible. The rifle squad now rolls 2 dice because the Predator’s invisibility has gone (it gets back the die removed by the Predator’s original score of 5) and scores a 1,5, a pin which has no other effect.
Initiative switches to the human player and the Predator will stay visible until it can move out of sight of any human units.

A pinned Predator cannot move but can still shoot.
A suppressed Predator cannot move or shoot and will become visible if previously invisible.
A Predator that is killed with three hits or killed in Close Combat dies immediately. A Predator that dies from 2 or more suppression results has time to initiate its self destruct. At the end of the next human player’s phase it will explode doing 5 dice of damage (less cover bonuses) to every unit, enemy, friendly or neutral, in LOS of the explosion.

Predators remove a pin with 3+ and suppression with 4+
Predators shoot with 4 dice but cannot combine fire, they are after personal trophies after all.
In Close Combat each Predator gets +5 (2 predators attack, +10, bad luck).
Predators will not attack civilians, civilians can only move when in contact with an armed human unit or command figure.

Victory points should be awarded to the human player for rescuing civilians and killing Predators. The Predator player should get them for killing armed humans for trophies, more VPs for a Close Combat kill would seem appropriate.
Balancing the firing dice is a good way of balancing the forces with any odd going in the human player’s favour. For instance, three rifle squads and a HMG mustering 13 dice (3x3+4) should face off against 3 Predators mustering 12 dice (3x4).