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