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