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