One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,7)(5,8)(9,10,15,18)(11,20,23,39)(12,17,14,29)(13,25,28,37)(16,31,33,22)(19,24,35,27)(21,38,30,36)(26,32,40,34)(2,6)(3,4)(7,8)(9,11,15,23)(10,16,18,33)(12,21,14,30)(13,26,28,40)(17,32,29,34)(19,36,35,38)(20,37,39,25)(22,24,31,27)(2,7)(3,4)(6,8)(9,12,15,14)(10,17,18,29)(11,21,23,30)(13,24,28,27)(16,32,33,34)(19,25,35,37)(20,38,39,36)(22,26,31,40)(2,8)(6,7)(10,18)(16,33)(17,29)(19,35)(20,39)(25,37)(32,34)(36,38) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.