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