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