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