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