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