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