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