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