I’m late to the party, but let’s see if I can help.
The \x**\x** text is ostensibly hex-encoded something. That is, Apache got a sequence of bits which it represents as a series of two-byte (16 bit) codes. If they were all below \x80 it would be ASCII (which it isn’t). If they were all near each other numerically, then it would be some other encoding (which it isn’t). Since those numbers are all over the place, I’m guessing that it is one of two things:
Somebody attacking your server, possibly looking for a buffer overflow.
Somebody hitting an HTTP server with an HTTPS request on the HTTP port. This encrypted stream will not be encoded text and thus will look like random bits.
My guess is for the latter, just from looking at it.
I understand that it is a bit late to help the OP, but I figure if this page is showing up in search results then this answer may help somebody in the future.