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