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