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