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