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