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