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