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