It is a French familiar expression. The action he has done demonstrates his esteem for you. The action is above expectation.

Se foutre : make fun of someone or mock someone.

So, “Il ne s’est pas foutu de toi” means he did something more than expected in a positive way.

“Se foutre de quelqu’un” is course slang that means “se moquer de quelqu’un” only sometimes; what it means is given by a definition in the TLFi; here is that definition;

F.− Vulg. Emploi pronom.
1. [Avec un compl. introduit par de] Ne pas se soucier, se moquer (de quelque chose, de quelqu’un). On s’en fout; ils se foutent de nous. Synon. se fiche/ficher (fam.), se balancer de (fam.).Mon petit Mithoerg, nous nous en foutons inexprimablement, de Janotte… N’est-ce pas petite fille?… (Martin du G., Thib.,Été 14, 1936, p. 29).− Qu’est-ce que nous allons devenir? il n’y eut aucune réponse; les types se foutaient de ce qu’ils allaient devenir (Sartre, Mort ds âme,1949, p. 96).− M’en fous, Grégoire, m’en contrefous (Arnoux, Solde,1958, p. 39).
− Loc. Se foutre de qqc./qqn comme de l’an* quarante, de colin-tampon*, de sa première chemise, d’une guigne*, d’une pomme (vx). N’avoir cure de quelque chose, de quelqu’un; n’en faire aucun cas.

More often, it means “to treat someone in such a way as to denigrate their legitimate status or claims in a very contemptible manner with haughtiness and even in being simply and downright dishonest.

So, if we want to translate “Il s’est pas foutu de toi” the second possibility is the one; you wouldn’t, ever, say “He didn’t make fun of you.” in that case; there would be no sense in that. You might say “He didn’t make a fool of you.“;
However, often, that’s not what the exact mind of the French. Most often what’s meant is “He didn’t fool you.“, “He didn’t take you for a fool“; that is to say “He didn’t try to cheat you.”, “He didn’t try to lie to you.”. However the register (current in English) is not that of the French; although people often have no other way of expressing that idea, the use of the verb “foutre” is still considered to to be too slangy for some French people. (Remember that, basically, “foutre” is the equivalent of “fuck”.)

I should draw attention to Reese’s answer as it underlines a definite nuance that is often enough part and parcel of what a speaker is trying to communicate when saying “Il ne s’est pas foutu de toi.”. If not to be taken as necessarily meaning “he did something more than expected in a positive way” at least it can usually be taken as meaning “he did something quite satisfying in the way of what was expected.”. When this is the case the English translation is better rendered if made on the level of the context.

A few Instances

• business matter; He’s given you quite a good deal!
• acknowledgement of responsability in a dispute: He’s been really fair with you!
• car repair: He’s made a very good job!
• talks to right a wrong: He’been fairly honest with you!