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