For the S/360 systems, there was a wide choice of colors. In fact, most of the S/360s I saw initially were that orangish-red. I've heard it referred to as "International Orange" in accordance with Federal Specification 595:
http://www.fed-std-595.com/FS-595-Paint-Spec.html In the early 1970s, CDC went from a beige and gray motif to blue glass and fake woodgrain. NCR, Cray and Honeywell similarly had brightly-colored systems. Office interiors in the 1980s were often the bright primary upholstery, with exposed structure and plumbing being painted similarly bright colors. It was a bit much, reminiscent of the Pompidou centre in Paris. Styles change. I don't think much of deep blue as a color scheme. --Chuck