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