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