Very easy:
VGA Video connector pinouts:
Pin # - Signal Name - CAT 5 Conductor
1 - Red - Orange
2 - Green - Green
3 - Blue - Blue
4 - No Connection
5 - Ground - No Connection
6 - Ground - Orange/White
7 - Ground - Green/White
8 - Ground - Blue/White
9 - No Connection
10 - Ground - No Connection -
11 - No Connect
12 - DDC DAT - No Connection
13 - Horizontal Synchronization - Brown
14 - Vertical Synchronization - Brown White
15 - DDC Clock - No Connection
Conect to the S-Video as follows:
Pin 1 = Y gnd (Use Green/White) >>>PIN 7
Pin 2 = C gnd (Use Orange/White)>>>>PIN6
Pin 3 = Y (Use Green)>>>> PIN 2
Pin 4 = C (Use Orange)>>>PIN 1