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