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