Matrix to Multi-level security
Subject S2 has read-write access to Object 1, which is something no other subject has. On the other hand, subject S2 has no rights to Objects 2 and 3, which is something no other subject has. So Subject S2 has incomparable rights to all other subjects.

Similarly S1 is incomparable to the others.

S4 clearly has more rights than S3.
S5 clearly has more rights than S3.

So the subjects' "security levels" can be shown like this:

$\,\,\,$S5 S4
   \ /     S1   S2
    S3

(I don't know this subject before your question so this is just my impression. This subject has been discussed in three questions at cs.stackexchange.com in the past.)