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