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