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