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