One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,7)(5,8)(9,10,15,19)(11,20,23,38)(12,17,14,29)(13,25,28,39)(16,31,34,22)(18,24,36,27)(21,37,30,35)(26,32,40,33)(2,6)(3,4)(7,8)(9,11)(10,16)(12,21)(13,26)(14,30)(15,23)(17,32)(18,35)(19,34)(20,25)(22,27)(24,31)(28,40)(29,33)(36,37)(38,39) involution — undirected(2,7)(3,4)(6,8)(9,12,15,14)(10,17,19,29)(11,21,23,30)(13,24,28,27)(16,32,34,33)(18,25,36,39)(20,37,38,35)(22,26,31,40)(2,8)(6,7) 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.