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