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