... can I place the other two ends on the edge of the roof? One on the front edge of the roof and the other on the back edge?
Yes, you can place the ends on any convenient attachment, but try and keep several feet between the antenna's end insulator and the building (the ends of the often are the area of highest voltage).
Does the antenna have to be straight in line with the center or can I stretch them back towards the roof? Is there an angle I have to keep?
No, it may be configured with one or more 'bends' and still perform adequately. W1JKA mentioned "... ~ 30 degrees from straight ...", this should be 'acceptable', but I wouldn't go much beyond this if possible. You can even 'zig-zag' the antenna to get the antenna in to fit your physical typology.
Note: as you stated that the antenna height (center) will be "36 feet" don't expect stellar performance on the lower bands. 30M and up (10, 12, 15, 17, and 20) should yield you decent DX contacts across to nearby continents, but for 40M and certainly for 80M the vast amount of your radiation will be straight up even though there is a bit of a vertical component due to the Windom's 22' vertical radiator. The best success for the lower bands (40M and 80M) with these Windoms is when you can manage the get both the center and
the ends up to heights > 65 feet; although some users have reported remarkable DX contacts (such as working deep into SE Asia) with heights the same as you are using.
GL, 73, Rich K3VAT