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