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