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