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