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