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)(25,26,32,31)(27,35,30,33)(28,38,34,29)(36,37,39,40)(1,2)(3,6)(4,5)(7,8)(9,11,15,13)(10,12,16,20)(14,18,23,21)(17,19,22,24)(25,27,32,30)(26,33,31,35)(28,39,34,36)(29,40,38,37)(2,5)(6,8)(10,16)(11,13)(17,22)(18,21)(25,28)(26,29)(27,36)(30,39)(31,38)(32,34)(33,37)(35,40) involution — undirected(9,12)(10,11)(13,16)(14,19)(15,20)(17,18)(21,22)(23,24)(25,29,32,38)(26,34,31,28)(27,37,30,40)(33,39,35,36)(1,2)(3,6)(4,5)(7,8)(9,13,15,11)(10,12,16,20)(14,21,23,18)(17,19,22,24)(25,30,32,27)(26,35,31,33)(28,39,34,36)(29,40,38,37)(1,3,4,7)(2,6,5,8)(9,14)(10,17)(11,18)(12,19)(13,21)(15,23)(16,22)(20,24)(25,31,32,26)(27,35,30,33)(28,38,34,29)(36,40,39,37)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.