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