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