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