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